The invention relates to a transesterification process for the production of acrylic ester monomers from alkyl (meth)acrylates and alcohols.
The transesterification reaction between alcohols and alkyl (meth)acrylates is known and commercially practiced. As typically conducted in commercial scale processes, the (meth)acrylate reactant and the catalyst are recycled.
U.S. Pat. No. 5,610,313 discloses a process for the preparation of alkyl imidazolidone (meth)acrylates that employs, as a catalyst, a mixture formed of (a) at least one magnesium alkoxide and (b) a component chosen from the chelates of calcium with 1,3-dicarbonyl compounds, dialkyltin oxides, dialkyltin alkoxides and dialkyltin diesters. That patent recommends that maximum dehydration is achieved before addition of the catalyst to the reactants.
U.S. Pat. No. 7,528,278 teaches a transesterification process that involves reacting certain alcohols with an alkyl (meth)acrylate in the presence of a mixed salt catalyst under specified conditions. The mixed salt catalyst can tolerate up to 3,000 ppm water. The patent teaches that prior art catalysts, such as dibutyl tin oxide and lithium hydroxide, are subject to deactivation in the presence of water, and that maximum dehydration of the contents of the reaction vessel should be achieved before addition of said catalysts.
EP-A1-1 686 118 discloses a transesterification process comprising preparing a reaction mixture of alcohol, alkyl (meth)acrylate and polymerization inhibitor, removing water until the water content of the mixture is no more than 1200 ppm, adding at least 2 charges of catalyst, and heating the mixture to commence the reaction.
It would be desirable to have a higher productivity process where all reaction materials could be present in the reaction mixture during dehydration.